Table III.

Histopathological changes in the kidney, liver and gill of O. niloticus exposed to 1 and 10 mg/L suspensions of SS-ZnNPs (40–60 nm) and LS-ZnNPs (80–100 nm) and control fish

Group	Kidney		Liver		Gill
	7th day	14th day	7th day	14th day	7th day	14th day
Control	Normal histology	Normal histology	Normal histology	Normal histology	Normal histology	Normal histology
1 mg/L SS-ZnNPs	Tubular deformations, glomerular expansions, mononuclear cell infiltrations	Tubular deformations, melanomacrophages aggregations	Mononuclear cell infiltrations, fatty changes	Hepatocellular vacuolations	Basal hyperplasia, capilllary dilations, clubbing of tip of secondary lamellae	Basal hyperplasia, clubbing of tip of secondary lamellae
10 mg/L SS-ZnNPs	Tubular deformations, glomerular expansions mononuclear cell infiltrations	Glomerular deformations, tubular deformations	Mononuclear cell infiltrations, fatty changes, hepatocellular vacuolations	Sinuzoidal dilations, hepatocellular deformations	Basal hyperplasia, lamellar fusions, clubbing of tip of secondary lamellae	Epithelial liftings, clubbing of tip of secondary lamellae
1 mg/L LS-ZnNPs	Tubular deformations, Glomerular deformations, increasing of melanomacrophages aggregations, necrosis	Glomerular deformations, tubular deformations	Mononuclear cell infiltrations, fatty changes, sinuzoidal dilations	Fatty changes, cytoplasmic vacuolations, mononuclear cell infiltrations	Basal hyperplasia, clubbing of tip of secondary lamellae	Epithelial liftings
10 mg/L LS-ZnNPs	Tubular deformations, Glomerular deformations, increasing of melanomacrophages aggregations, necrosis, hemorrhage	Tubular deformations, mononuclear cell infiltrations	Mononuclear cell infiltrations, fatty changes	Cytoplasmic vacuolations, mononuclear cell infiltrations	Basal hyperplasia, lamellar fusions, clubbing of tip of secondary lamellae	Epithelial liftings, clubbing of tip of secondary lamellae